Stable binocular single vision gives way to alternating periods of monocular suppression when the two eyes view dissimilar monocular stimuli. This phenomenon, called binocular rivalry, discloses the existence of a potent inhibitory process within the central visual pathways, a process that may be related to the suppression of vision that often accompanies disorders of binocular vision such as strabismus. The PI has recently developed a neural theory of binocular rivalry that consists of seven propositions, some of which are based on existing psychophysical data and others which are more axiomatic in form. A major aim of the present proposal is to test various aspects of the theory. Experiments are grouped into six broad categories that focus on: (1) the relation of rivalry to fusion; (2) cooperative interactions between local suppression zones; (3) the distinction between stimulus suppressed and stimulus absent; (4) the dependence of depth of suppression on monocularly innervated neurons: (5) the role of top down influences on dominance vs suppression; and (6) the neural events that terminate a suppression phase. Results from these experiments, besides critically testing the theory, will set the stage for a more critical examination of the relation between rivalry suppression in normal observers and clinical suppression in people with histories of disordered binocular vision.